well, to resolve doubts I've checked the first episode of SAC's bdrip in 1080p and I can say that all those previously posted blurry subpar screenshots have nothing in common with actual state of affairs - the quality of SAC's bluray release is just what it should be and is on par with any excellent animes released on bluray recently. What a relief... even fullscreen faces look crisp and sharp with proper outlines' width (thin and clean).

yeah, all those new screenshots heal my soul tortured by the original three from an unknown source :-) We'll just have to keep faith that there won't be too much scenes like Motoko's face, 2nd in original set of shots.

I'm more inclined to agree with Pyoko on their points - particularly with the fourth one made. Take this comparison shot from the first episode, for example.

img90.imageshack.us DVD
img42.imageshack.us bururei

Maybe it's just me, but there's quite a large difference between the two sources there. But I concede that this SAC is a far cry from a fantastic blu-ray release, which is about what I expected from such an old non-cel show anyway, so some scenes seem to benefit a lot more than other scenes. Because I apparently have nothing better to do, I took a few other comparisons with a much less pronounced difference than that. BD screenshot is always second.

img16.imageshack.us
img16.imageshack.us

img8.imageshack.us
img10.imageshack.us

img259.imageshack.us
img8.imageshack.us

I mean, still nicer, but for the most part, not too much a difference definition wise, mostly with the haloing as mentioned. So it fluctuates, but overall, I think the blu-ray still does enough for me to be satisfied. Again with what Pyoko said, it's as good as it's ever going to look, and it's usually a nice enough difference for me. (My DVD and blu-ray sources could probably be better, but shh.)

toph, you can try it yourself on the Batou shot. Downscale it to 853x480 and back, and tell me there is not more definition around his eyes on the original. Here's another example from a later episode, the first one is the original 1080p shot, the second one has been downscaled to 480p and back:
http://img216.imageshack.us/img216/2900/sac1080p.png
http://img512.imageshack.us/img512/6712/sac480p.png

Of course you can believe what you want regarding upscaling, but the bottom line is that it's as good as it's ever going to look, and a vast improvement over what's on DVD.

Pyoko, I'd doubt your words to say the very least.

dvd's and bd's screenshots of Kusanagi differ in just one major aspect (brightness aside which is a tv->pc renderer issue) - dvds have halos around lines. The level of detail on those presumably bd-screenshots is exactly 480p. And this very well may be true if the process of creating is what I've heard of - all in CG + flattening filter, so that there wasn't any film/paper sources but only digital ones created right for the dvd-release & sd-tv.

The laughing man, the individual eleven and solid state society ovas, the 2nd gig — all of these feature much more fine graphics.

A couple of things to note before everyone jumps on the upscale train:

1) The colours on these caps are incorrect (too dark).
2) Quick downscale-upscale tests confirm these are probably at a 720p level of detail, which is to be expected, the movies were the same.
3) This was made 7 years ago, and it looks equal to or better than plenty of newer shows. The number of anime titles that are as sharp as Tekkonkinkreet are few and far between.
4) TV anime is not exactly known for its consistency. Some shots are bound to look softer and some sharper.
5) Here's a painful reminder from the R1 DVD, and shows how much of an upgrade the Blu-ray really is:
http://img12.imageshack.us/img12/2316/sacdvd1.png
http://img35.imageshack.us/img35/8791/sacdvd2.png

geass r1 was also seemingly upscaled by bluray creators yet they've managed to add some postprocessing filters (antialiasing of lines somewhat similar to SharpAACmod) to make the picture look at least not blurry. I wonder if those screenshots are fake becuase otherwise it would mean that bluray transfer of GitS SAC was made by total n00bs

Yeaaah, this really looks like an upscale if you ask me.... the picture is too smooth and almost blurry; colors are also washed out a bit (there seems to be a problem with the black level)
...But it is so hard to say with anime what is causing the bad PQ.... it might very well be the source... who knows...